Refrigeration control for air conditioned passenger vehicles



y 1943- M. E. HANSON 2,319,130

REFRIGERATION CONTROL FOR AIR CONDITIONED PASSENGER VEHICLES Filed March 5, 1941 5 sfdrfek and Con Gar

Bali fery 69 Wayside A-C Connech'on 1220822303 Mz'Zfi-or E Haavson,

Patented May 11, 1%43 REFRIGERATION CONTROL FOR AIR CON- DITIONED PASSENGER VEHICLES Milton E. Hanson, Haddonfleld, N. J., assignor to B. F. Sturtevant Company, Boston, Mass.

Application March 5, 1941, Serial No. 381,832

4 Claims.

This invention relates to refrigeration apparatus for providing air cooling and relates more particularly to controls for refrigeration apparatus for air cooled, railway passenger cars.

It has been the practice in air conditioned passenger cars to energize an electric motor driving a refrigerant compressor, from the car battery during the normal motion of the cars, and during station stops or for precooling, to utilize way-side alternating current, electric energy for energizing the equipment. The compressor motor is provided with A. C. and with D. C. windings and when the way-side connections are plugged in, the motor is operated by the alternating current and the D. C. windings are used to provide D. C. for charging the car battery. In such prior systems, the car thermostat started and stopped the compressor motor and switched from A. C. control to D. C. control when the wayside connections were removed, and vice versa.

Controlling the temperature in the car by cycling the compressor has resulted during the OE cycles of the compressor, in rises in relative humidity due both to the absence of any dehumidification, and to the reevaporation of moisture from the commonly used, direct expansion evaporator tubes, which was condensed thereon during the on cycles of the compressor. To overcome the undesired rises in relative humidity, it has been proposed to operate the compressor continuously and to reheat the air before delivery by steam heaters controlled by dry bulb thermostats in the passenger spaces or in the recirculated air passages. ating cost of such an expedient is believed to be out of all proportion to the benefit gained.

This invention provides for a graduated control of the operation of the refrigeration apparatus by controlling the surface area of the air cooling evaporator and by unloading cylinders of a multiple cylinder, refrigerant compressor. The refrigerating effect varies conformably with the load so that cycling of the compressor is reduced and with refrigeration provided substantially all of the time. I

To provide for continuous battery charging during station and yard stops without overcool ing the car, a car thermostat, instead of stopping the compressor motor, which at such a time is acting to charge the battery, acts to unload all cylinders of the compressor, thus causing it to float on the line without substantial energy consumption.

Objects of the invention are to provide for graduated control of the refrigeration supplied to air cooling vaporators in a railway passenger car, and to provide that the electric equipment associated with the refrigeration apparatus, continuously charge the car batteries when The opertor to control of unloading cylinders of the compressor.

The overhead casing 5 has the fresh air inlet 6, the recirculated air inlet 1 and the duct 8 extends therefrom for the distribution of the conditioned air.

The casing 5 contains the fan 9, the spray header ill, the evaporator II and the eliminator i2. The sump i3 below the spray header l0 and the evaporator ll, contains the pump it driven by the motor 15. The pump M and the sump I3 are disclosed in detail in the M. E. Hanson Patent No. 2,189,731 of Feb. 6, 1940. The spray header I0 is connected to the discharge of the pump I4 and sprays water upon the evaporator H, the water being continuously recirculated by the pump. The eliminator i2 which may be of the usual vertical zig-zag plate type collects entrained moisture from the air and returns it to the sump. The water sprayed upon the evaporator is cooled by the contact therewith and acts to aid in the cooling and dehumidifying of the air as well as to wash it. The sprays also keep the evaporator surface clean.

The evaporator illustrated is of the type having closely spaced vertical fins, each fin contacting every evaporator tube. In the embodiment illustrated, the tubes IE are arranged four rows deep and 6 rows high. Other arrangements could, of course, be used. The evaporator H is divided into two separate sections by the refrigerant distributors I1 and I8. These distributors are preferably of the type of the Morton Patent No. Re. 20,964. The distributor l1 supplies refrigerant to the odd numbered tubes of the first vertical row (with respect to air flow) while the distributor l8 supplies refrigerant to the even numbered tubes of the same row. The tubes in the horizontal rows are connected as usual in series and to the common discharge header I9.

The refrigerant compressor 20 has four cylinders numbered I, 2, 3, and 4, these cylinders being adapted to be unloaded as will be explained.

The outlets of the cylinders numbers I, 2, 3, and

88 and 84 rapectively. The valves 24, 28, 28, and 84 are also connected to the common discharge tube 88 by. the branch tubes 28, 88, 8| and condenser 88 and then through the tube 4| to the tubes 48 and 48 which lead to the distributors l1 and I8 respectively. The similar expansion valves 44 are connected in the tubes 42 and 48.

'lhe tube 48 also contains the valve 48 which is opened and closed by the solenoid 48 as will be explained.

The solenoids 88 and 39 are connected at one side by the wires 88 and 8| and the wire 88 to one side or the car battery 49. The solenoids 48 and 88 are connected at one side to the wire 18 leading to the relay 88 and at their other side by the wire 14 which leads to the relay 88. The solenoids 88 and 88 are connected at one side by the wire 88, 8|, and 88 to one side of the car battery 48 and are connected at their other side by the wires 84, 88, and 88 to one side of the solenoid 48 which adjusts the valve 44 in the tube 48 supplying refrigerant to a. section of the evaporator 'as will be described. g

The other side of the solenoid 44 is connected by the wire 88 to one side of the battery 48 to which the other sides or the solenoids 38 and 89- are connected by the wire 88. The thermostat 88 in the recirculated air entering the inlet I, is connected by the wire 88 to the solenoids 88, 88, and 48. The other side or the thermostat 88 is connected by the wire 88 to the battery 48. The solenoids 88, 89, and 48 are seen to be connected in parallel with each other and in series with the battery 48 and the thermostat 89. As will be explained, the thermostat acts to control the solenoids 88 and 88 to unload cylinders numbers I and 2 of the compressor and to control the solenoid 48 to render inactive a portion or the evaporator when the passenger space has been cooled to the desired temperature.

The thermostat 8| which is a low limit thermostat has one side connected in .series with the battery 49 by the wires 88, 58 and 91 and is connected by the wires 48 and 48 to the relay 88, and through the relay 85 to the relay 83 and to the energizing circuit 01' the solenoids 48 and 88. when the car is moving and the system operating from the battery, the thermostat 8| acts to start and stop the compressor. When the way side connections are completed, the thermostat 8| acts to control the solenoids 48 and 88 to unload cylinders 8 and 4 oi! the compressor when the low limit temperature is reached causing, since the cylinders 8 and 4 would be unloaded at that time, the compressor to operate with all cylinders unloaded while the battery is being charged by the motor-generator 88.

The operating contacts of the relay 88 connect the motor-generator 88 through the starter and interlock controls 81 to the battery 48. The details of the starter and interlock controls 81 are shown by Figs. 2 of the U. S. Patent No. 1,985,839 to C. F. King, Jr.

described in detail here. It is believed to be suillcient to state herein that they are provided I for segregating the A. C. and D. C. currents so that the motor-generator can act as a D. C. generator when the way-side connections are plugged in.

acts to deenergize the solenoid 88 or the relay 88 so that the thermostat 8| cannot act to energize the solenoid as will be explained.

The details of the relay 88 are shown by Fig. 3. When the system is operating on A. C. the solenoid 94 is energized and pulls up itsarmatures 88 and 88.as illustrated. The wires 41 and 48 from the thermostat 8| are connected to the armatures which operate as a double-pole, double-throw switch to position the thermostat 8| to control the solenoids 48 and 88 as illustrated, or to control, through the relay 88, the motor-generator 88. In the position illustrated, the system is operating from A. 0.; the solenoid 94 is energized and the armatures 88 and 88 strike the contacts 88 and 88 respectively connected to the wires 18 and I4 which lead to the solenoids 48 and 88, applying current from the battery to the solenoids 48 and 88 when the contacts of the thermostat 8| are closed, causing the solenoids 48 and 88 to be energized and to maintain the cylinders 4 and 8 of the compressor in operation through closing or! the by-pass tubes and by opening the tubes 88 and 8| to the condenser. When the low limit temperature which, for example, may be 71 F., is reached, the contacts of the thermostat 8| open: the solenoids 48 and 48 are deenergised, and the cylinders 8 and 4 are unloaded. I

At the same time, through the armatures 88 and 98 having left the contacts I88 and "I which are connected to the wires 82 and 84 respectively, leading to the relay 88, the thermostat 8| is disconnected from the control of the relay 88 and through it, oi! the motor-generator 88 so that so long as the way-side connections are plugged in, the motor-generator 88 will continue operating as a generator to continuously charge the battery 49. When the way-side connections are removed, the solenoid 84 of the relay 88 becomes deenergized, the armatures 88 and 88 leave the contacts 88 and 88 and strike the'contacts I88 and IN. This disconnects the thermo- 50 stat 8| is disconnected from control of the and so will not be unloading solenoids 88 and connects it to the relay 88, Then when the low limit temperature is reached, the energizing circuit including in series. the thermostat 8|, the battery and the solenoid '88 is opened causing the contacts 8| and 88 to separate as illustrated and to deene size the motor-generator.

Th thermostat 88 operates in the same way to control the active evaporator surface and the unloading of cylinders and 2 of the compressor" regardless of whether the system is operating on A. C. or D. C. When the recirculated air temperture is above, say for example, 75" R, the contacts oi the thermostat 88 are open; the cylinder 88, 88 and the evaporator control solenoid II are not energized with the result that all cylinders of the compressor are loaded and the entire evaporator surface is active.

When the recirculated air temperature falls below the control temperature, the contacts of the thermostat 59 close and complete the battery circuit including the solenoids 38, 39 and 46 causing the solenoid It. to close the-valve I4 and thereby to shut ofl. a portion of the evaporator surface, and causing the solenoids 38 and 39 to adjust the valves 24 and 25 respectively to close on the tubes 2s and SI respectively, connecting with the tube 85 to the condenser 20,-

, and to open up the tubes 32 and 33' respectively,

connecting with the by-pass tube 3!,thereby unloading the cylinders I and 2 of the compressor. While for ease of illustration, the unloading of the compressor cylindershas been described in connection with recirculation of the refrigerant through external tubes, it is preferred that the unloading take place in the heads of the cylinders as disclosed in the E. M. Paullin, Jr. Patent No. 2,083,740 of June 15, 1937.

While one embodiment of the invention has been described for the purpose of illustration, it should be understood that the invention is not limited to the exact apparatus and arrangement of apparatus illustrated, as modifications there-. of may be suggested by those skilled in the art without departure from the essence of the invention.

What is claimed is:- l 1. An airconditioning system for a passenger vehicle, comprising an air cooling evaporator. means including a refrigerant compressor for su plying refrigerant to said evaporator, a motor for driving said compressor, an electric battery carried by said vehicle for energizing said motor,

means including a thermostat responsive to temperature changes in the passenger spacefor disconnecting said motor from said battery when the air has been cooled to the desired temperature. wayside connections for supplying external electric energy to said motor as when said vehicle is standing in a station, means for unloading said compressor, and means actuated when said wayside connections are completed for disconnecting said thermostat from control of said motor and for connecting said thermostat to for supplying external electric energy to said motor as when said vehicle is standing in a station, means for unloading the other cylinders of said compressor, and means actuated when said wayside connections are completed for disconnecting said low limit thermostat from control of said motor and for connecting said low limit thermostat to control of said means for unloading the vehicle, comprising a multiple section, air cooling evaporator, means including a refrigerant compressor having a plurality of cylinders for supplying refrigerant to said evaporator, means I including a thermostat responsive to temperature changes in the passenger space for unloading one or more of said cylinders and for rendering one of said evaporator sections inactive when the air in the passenger space has been cooled to that desired, a motor for driving said compressor,-an electric battery carried by said vehicle for energizing said motor, means including a low limit thermostat responsive to temperature changes inthe passenger space for disconnecting said motor from saidbattery when the air has been cooled to the desired low limit temperature, wayside connections for supplying external electric energy to said motor as when said vehicle is standing in a station, means for unloading the other cylinders of said compressor, and means actuated when said wayside connections are completed for disconnecting said low limit thermostat from control of said motor and for connecting said low limit thermostat to control of said means for unloading the other cylinders of said 1 compressor whereby when said wayside conneccontrol of said means for unloading said compressor whereby when said wayside connections ar completed and the air has been cooled to the desired temperature. said motor is continually energized from said wayside connections and said thermostat acts to unload said compressor.

2. An air conditioning system for a passenger vehicle, comprising an air, cooling evaporator, means including a refrigerant compressor having a plurality of cylinders for supplying refrigerant to said evaporator, means including a thermostat responsive to temperature changes in the passenger space for unloading one or more of said cylinders when the air in the passenger space has been cooled to that desired. a motor for driving said compressor, an electric battery'carried by said vehicle for energizing said motor, means including alow limit thermostat responsive to temperature changes in the passenger space for. disconnecting saidmotor from said battery when the air has been cooled to the desired low limit temperature, wayside connections tions are completed and the air has been cooled to the desired low limit temperature, said motor is continually energized from said wayside connections and said low limit thermostat acts to unload said other cylinders of said compressor.

4. An air conditioning system for a passenger vehicle, comprising an air cooling evaporator,

means including a refrigerant compressor having a plurality of cylinders for mpplyin's refrigerant to said evaporator, a motor connected to said compressor for driving same, means includ-. ing' wayside connections for supp y g electric power to said motor as when said vehicle is standing in a station, a thermostat responsive to changes in the temperature in the er space of said vehicle for controlling saidtemperature, means for unloading one or more of said cylinders, means actuatedwhen said wayside connections are completed for connecting said thermostat to said last mentioned means for controlling said temperature by variably loading said compressor, means for unloading the other cylinders of said compressor, a low limit thermostat, and means actuated when said wayside connections are completed for connecting said low limit thermostat to said lastmentinned means for unloading said other cylinders when said wayside connections are completed 

